Gas stripper system

ABSTRACT

A gas stripper system for purification of a primary coolant contaminated in cooling a nuclear reactor is provided. The gas stripper system includes a gas stripper column and a condenser arrangement. The column is adapted to receive the liquid phased contaminated primary coolant. The column defines top, bottom and middle sections and includes a distributor member, a re-boiler member and a separation member disposed therealong. The distributor member, a re-boiler member and a separation member with structured packing are configured such that maximum contact between the liquid phased primary coolant and gaseous phased primary coolant is made. Moreover, the condenser arrangement is configured to the gas stripper column to receive and condense the vapour phased primary coolant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Patent Application No.15172745.0 filed Jun. 18, 2015, the contents of which are herebyincorporated in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to degasification devices, moreparticularly, to a gas stripper system.

BACKGROUND

Gas strippers are generally used in a physical separation process whereone or more components are removed from a liquid stream by a vaporstream flowing in counter current flows. For example in nuclear plants,such gas strippers may be generally utilized for purification of primarycoolants that are circulated along the nuclear reactors for cooling.Generally, the primary coolants are circulated along the nuclearreactors to continuously cool the reactors; however, during the coolingprocess the coolant gets contaminated and therefore is required to bepurified continuously to avoid discharge of hazardous elements in theenvironment.

Various conventional gas strippers may have been developed and utilizedfor the said purpose; however, most important and determining factori.e. the contact between the liquid and vapor streams have alwaysremained an industrial concern in order to achieve balance or maximumcontact therebetween so that the overall efficiency of the gas strippersmay be improved.

Accordingly, there exists a need for a gas stripper with improved designso that efficiency of the overall system may be improved.

SUMMARY

The present disclosure discloses an improved gas stripper system thatwill be presented in the following simplified summary to provide a basicunderstanding of one or more aspects of the disclosure that are intendedto overcome the discussed drawbacks, but to include all advantagesthereof, along with providing some additional advantages. This summaryis not an extensive overview of the disclosure. It is intended toneither identify key or critical elements of the disclosure, nor todelineate the scope of the present disclosure. Rather, the sole purposeof this summary is to present some concepts of the disclosure, itsaspects and advantages in a simplified form as a prelude to the moredetailed description that is presented hereinafter.

A general object of the present disclosure is to provide the gasstripper system with improved design, which may be utilized, but notlimited to, in power plants, such as, nuclear power plants.

In one aspect of the present disclosure, a gas stripper system forpurification of a primary coolant contaminated in cooling a nuclearreactor is provided. The gas stripper system may include a gas strippercolumn and a condenser arrangement. The gas stripper column may beadapted to receive the liquid phased contaminated primary coolant. Thegas stripper column defines top, bottom and middle sections and includesa distributor member, a re-boiler member and a separation memberdisposed therealong. In an embodiment, the distributor member isconfigured along the top of the gas stripper column and adapted toevenly distribute the liquid phased contaminated primary coolant whileflowing from the top to bottom of the column. Further, the re-boilermember is configured along the bottom of the gas stripper column andadapted to heat the primary coolant to a gaseous phase. The gaseousphased coolant is raised counter current to the liquid phasedcontaminated primary coolant from the bottom to the top of the column.The separation member is disposed along the middle section of thecolumn, between the distributor and re-boiler members. The separationmember includes a structured packing so as to enable maximum contact ofthe liquid phased primary coolant with the gaseous phased primarycoolant raising counter current to liquid phased contaminated primarycoolant to be dissolved to obtain vapour phased thereof. The condenserarrangement is configured to the gas stripper column to receive andcondense the vapour phased primary coolant so as to enablenon-condensable gases to be discharged and return of the condensate tothe gas stripper column.

In an embodiment, the separation member may include structured packing.Further, in one embodiment, the distribution member is configuredinclude various conduits having outlets and arranged such that to evenlydistribute the primary coolant along the structured packing.Furthermore, the re-boiler member may be configured of stacked tubesstructure placed in the column or it may be an electrical re-boilerplaced outside of the column to vaporize the coolant. Similarly, thecondenser arrangement may also be integral to the column or separatedtherefrom.

The distributor member, a re-boiler member and a separation member areconfigured so as to balance the liquid phased primary coolant andconversion of the gaseous phased primary coolant such that the maximumcontact therebetween may be made along the separation member. Further,the condenser arrangement enables efficient separation of non-condensable gases including the radioactive gases xenon and krypton fromthe coolant making the overall system efficient.

These together with the other aspects of the present disclosure, alongwith the various features of novelty that characterize the presentdisclosure, are pointed out with particularity in the presentdisclosure. For a better understanding of the present disclosure, itsoperating advantages, and its uses, reference should be made to theaccompanying drawings and descriptive matter in which there areillustrated exemplary embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features of the present disclosure will betterunderstood with reference to the following detailed description andclaims taken in conjunction with the accompanying drawing, wherein likeelements are identified with like symbols, and in which:

FIG. 1 depicts a gas stripper system, in accordance with an exemplaryembodiment of the present disclosure;

FIG. 2 illustrates a top view a distributor member, in accordance withan exemplary embodiment of the present disclosure;

FIGS. 3A-3D illustrate various vies of a re-boiler member, in accordancewith various exemplary embodiments of the present disclosure;

FIGS. 4A and 4B illustrate top cross-sectional view of a separationmember; and a single element, where many of such elements when stackedtogether forms a separation member with a structured packing, inaccordance with an exemplary embodiment of the present disclosure;

FIGS. 5A and 5B, respectively, depict condenser arrangement andcross-section thereof, in accordance with an exemplary embodiment of thepresent disclosure; and

FIG. 6 depicts a gas stripper system, in accordance with anotherexemplary embodiment of the present disclosure.

Like reference numerals refer to like parts throughout the descriptionof several views of the drawings.

DETAILED DESCRIPTION

For a thorough understanding of the present disclosure, reference is tobe made to the following detailed description, including the appendedclaims, in connection with the above-described drawings. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofthe present disclosure. It will be apparent, however, to one skilled inthe art that the present disclosure can be practiced without thesespecific details. In other instances, structures and devices are shownin block diagrams form only, in order to avoid obscuring the disclosure.Reference in this specification to “one embodiment,” “an embodiment,”“another embodiment,” “various embodiments,” means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the presentdisclosure. The appearance of the phrase “in one embodiment” in variousplaces in the specification are not necessarily all referring to thesame embodiment, nor are separate or alternative embodiments mutuallyexclusive of other embodiments. Moreover, various features are describedwhich may be exhibited by some embodiments and not by others. Similarly,various requirements are described which may be requirements for someembodiments but may not be of other embodiment's requirement.

Although the following description contains many specifics for thepurposes of illustration, anyone skilled in the art will appreciate thatmany variations and/or alterations to these details are within the scopeof the present disclosure. Similarly, although many of the features ofthe present disclosure are described in terms of each other, or inconjunction with each other, one skilled in the art will appreciate thatmany of these features can be provided independently of other features.Accordingly, this description of the present disclosure is set forthwithout any loss of generality to, and without imposing limitationsupon, the present disclosure. Further, the relative terms used herein donot denote any order, elevation or importance, but rather are used todistinguish one element from another. Further, the terms “a,” “an,” and“plurality” herein do not denote a limitation of quantity, but ratherdenote the presence of at least one of the referenced item.

Referring to FIG. 1, a gas stripper system 100 is shown in accordancewith an exemplary embodiment of the present disclosure. The gas strippersystem 100 will be described herein in conjunction to FIGS. 1-6. In asmuch as the construction and arrangement of the system 100, variousassociated elements may be well-known to those skilled in the art, it isnot deemed necessary for purposes of acquiring an understanding of thepresent disclosure that there be recited herein all of theconstructional details and explanation thereof. Rather, it is deemedsufficient to simply note that as shown in FIGS. 1-6, in the system 100,only those components are shown that are relevant for the description ofone or various embodiments of the present disclosure.

As shown in FIG. 1, the system 100 may be utilized for purification of aprimary coolant contaminated in cooling a nuclear reactor 300. The gasstripper system 100 includes a gas stripper column 110 and a condenserarrangement 120. The gas stripper column 110 is adapted to receive theliquid phased contaminated primary coolant. The gas stripper column 110defines top 111, bottom 112 and middle 113 sections 113 and includes adistributor member 114, a re-boiler member 116 and one or moreseparation members 118 disposed therealong.

In an example embodiment, the distributor member 114 is configured alongthe top 111 of the gas stripper column 110 and adapted to evenlydistribute the liquid phased contaminated primary coolant while flowingfrom the top 111 to bottom 112 of the column 110. As shown in FIG. 2, anexample of the distributor member 114 is shown. Such distributor member114 may include a plurality of conduits 115 arranged in parallel andcrosswise manner. Each conduit 115 may include outlets 115a configuredtherealong to evenly discharge the liquid phased contaminated primarycoolant on the separation member 118. The distributor member 114, asshown in FIG. 2, is an example depiction and may be not considered to belimited to only such an arrangement, in fact, there may be various otherarrangement of the distributor member 114 that may be capable of evenlydistributing the liquid phased contaminated primary coolant.

Further, the re-boiler member 116 is configured along the bottom 112 ofthe gas stripper column 110 and adapted to heat the primary coolant to agaseous phase. The gaseous phased coolant is adapted to raise countercurrent to the liquid phased contaminated primary coolant from thebottom 112 to the top 111 of the column 110. In one embodiment, as shownin FIGS. 3A-3D, the re-boiler member 116 may include a plurality oftubes 117 stacked in a rectangular bundle, as shown in FIGS. 3A and 3B,or in a circular bundle, as shown in FIGS. 3C and 3D, so as to circulateheated fluid or steam to heat the primary coolant at the bottom of thecolumn 110 to convert thereto into the gaseous phase. In one form, thetubes 117 may be of U-shaped. However, without departing from the scopeof the present disclosure, the tubes 117 may of any other shape anddesign as per the industrial requirement.

In another embodiment, as shown in FIG. 6, the re-boiler member 116 maybe an electrical re-boiler 200 placed outside of the column 110 tovaporize the coolant, and is described below.

Furthermore, as shown in FIGS. 4A and 4B, the separation member 118 isdisposed along the middle section 113 of the column 110, between thedistributor 114 and re- boiler 116 members. The separation member 118may include a structured packing 118a so as to enable maximum contact ofthe liquid phased primary coolant with the gaseous phased primarycoolant raising counter current to liquid phased contaminated primarycoolant to be dissolved to obtain vapour phased. In one exampleembodiment of the present disclosure, as shown in FIGS. 4A and 4B, theseparation member 118 with the structured packing 118a may be configuredusing corrugated metallic sheets 119, as shown in FIG. 4B. Various suchsheets 119 may be stacked one above the other to obtain the structure ofthe separation member 118, as shown in the top cross-sectional view ofthe separation member 118, in FIG. 4A. The separation member 118 asshown in FIGS. 4A-4B are an example depiction and may not considered tobe limited to only such an arrangement, in fact, there may be variousother arrangements of the separation member 118 that may be capable ofenabling maximum contact of the liquid phased primary coolant with thegaseous phased primary. The separation member 118 with such structuredpacking 118a enables distributes the liquid phased primary coolant alongits entries area more evenly, which forms a thin layer of the liquidphased primary coolant thereby making maximum contact thereof with thegaseous phased primary and reducing the mass transfer resistance on theliquid side to enhance the degasification efficiency.

Further, in the system 100 the condenser arrangement 120, as shown inexample FIGS. 5A and 5B, is configured to the gas stripper column 110 toreceive and condense the vapour phased primary coolant so as to enablenon-condensable gases to be discharged and return of the condensate ofthe primary coolant to the gas stripper column 110. The condenserarrangement 120 includes tubes 121 (as shown in FIG. 5B, across-sectional view of the condenser arrangement 120 of FIG. 5A) thatenables steam/gas mixture of the primary coolant to be entered therein.In the tubes 121, the mixture gets condensate and non-condensable/radioactive gases are vented to a gas treatment system 123.Outside of the tube 121, the cooling water removes the condensationheat.

In operation of the system 100, referenced from example FIG. 1, theprimary coolant after cooling the nuclear reactor 300, the contaminatedprimary coolant with dissolved gases, such as xenon, krypton etc. isallowed to be directed from a tank 320 to the gas stripper column 110via passing through a recovery heat exchanger 310 and gaining heatthereform. The contaminated primary coolant in liquid phase enters thedistributor 114 at the top 111 of the column 110 to be distributed onthe separation member 118 and tickles to the bottom 112 of the column110. The part of the primary coolant is heated and evaporated by there-boiler member 116. The evaporated or gaseous phased coolant raisescounter current to the liquid phased contaminated primary coolant fromthe bottom 112 to the top 111 of the column 110. The separation member118 with the structured packing 118a enables maximum contact of theliquid phased primary coolant with the gaseous phased primary coolant tobe dissolved to obtain vapour phased primary coolant. The vaporisedcoolant enters the condenser arrangement 120 where it get condensed toenable non-condensable gases to be discharged and return of thecondensate of the primary coolant to the gas stripper column 110.Furthermore, the primary coolant free from the impurities is adapted tobe make exit from a return line 124 at the bottom 112 of the column 110and via a pump 330 it is circulated to pass through the exchanger 310and the cooler 340 to lose its heat and then exit via a three-way valve350 to be stored. The primary coolant used may be boric acid.

In operation of another system 100, referenced from example FIG. 6,apart from the electrical re-boiler 200 and an internal condenser 230,other components are more or less similar as described above in FIG. 1.In the arrangement of FIG. 6, the electrical re-boiler 200 is placedoutside of the column 110; however, the function of the electricalre-boiler 200 is similar to that of the re-boiler member 116. Inelectrical re-boiler arrangement 200, a recirculation pump 210 and theelectrical heater 220, respectively, used to circulate and heat theprimary coolant in the column 110 laying along the bottom section 112.Further, in such system 100, the condenser 230 may be configuredintegral to the column 110 along the top section 111; however, thefunction of the condenser 230 is similar to that of the condenser 120.Other operations are same as described above.

The system 100 of the present disclosure is advantageous in variousscopes such as described above. The combination of the distributormember, a re-boiler member and the separation member along with thecondenser member are configured such that the overall arrangementbalances the distribution of the liquid phased primary coolant andconversion of the gaseous phased primary coolant such that the maximumcontact therebetween may be made along the separation member.Specifically, the structured packing of the separation member enablesmaximum surface contact between the gas and the liquid with lowestpossible mass transfer resistance because of thin liquid film isobtained along the separation member that ensures the requireddegasification factor will be achieved by this equipment. Moreover, thesystem is economical and comparatively easy to manufacture.

The foregoing descriptions of specific embodiments of the presentdisclosure have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit thepresent disclosure to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The embodiments were chosen and described in order to bestexplain the principles of the present disclosure and its practicalapplication, to thereby enable others skilled in the art to best utilizethe present disclosure and various embodiments with variousmodifications as are suited to the particular use contemplated. It isunderstood that various omission and substitutions of equivalents arecontemplated as circumstance may suggest or render expedient, but suchare intended to cover the application or implementation withoutdeparting from the spirit or scope of the claims of the presentdisclosure.

What is claimed is:
 1. A gas stripper system for purification of aprimary coolant contaminated in cooling a nuclear reactor, the gasstripper system comprising: a gas stripper column adapted to receive theliquid phased contaminated primary coolant, the gas stripper columndefining top, bottom and middle sections, the gas stripper columnhaving, a distributor member configured along the top of the gasstripper column and adapted to evenly distribute the liquid phasedcontaminated primary coolant flowing from the top to bottom of thecolumn, re-boiler member configured along the bottom of the gas strippercolumn and adapted to heat the primary coolant to a gaseous phase, thegaseous phased coolant raises counter current to the liquid phasedcontaminated primary coolant from the bottom to the top of the column,and a separation member disposed along the middle section of the columnbetween the distributor and the re-boiler members, the separation memberhaving a structured packing so as to enable maximum contact of theliquid phased primary coolant with the gaseous phased primary coolantraising counter current to liquid phased contaminated primary coolant tobe dissolved to obtain vapour phased; and a condenser arrangementconfigured to the gas stripper column to receive and condense the vapourphased primary coolant so as to enable non-condensable gases to bedischarged and return of the condensate to the gas stripper column. 2.The system as claimed in claim 1, wherein the distributor membercomprises a plurality of conduits arranged in parallel and crosswisemanner, each conduits having outlets configured therealong to evenlydischarge the liquid phased contaminated primary coolant on theseparation member.
 3. The system as claimed in claim 1, wherein there-boiler member comprises a plurality of tubes stacked in circular orrectangular bundle so as to circulate heated fluid to heat the primarycoolant at the bottom of the column to convert thereto into the gaseousphase.
 4. The system as claimed in claim 3, wherein each of the tubesare U-shaped.
 5. The system as claimed in claim 1, wherein theseparation member having the structured packing adapted to enable theliquid phased primary coolant along the surface thereof such that a thincoolant layer is obtained to maximize contact of the liquid phasedprimary coolant with the gaseous phased primary coolant.
 6. The systemas claimed in claim 1, wherein the condenser arrangement comprisesincludes a plurality of tubes that enables steam/gas mixture of theprimary coolant to be entered therein, wherein in the tubes, the mixturegets condensate and non-condensate/radioactive gases are vented.
 7. Agas stripper system for purification of a primary coolant contaminatedin cooling a nuclear reactor, the gas stripper system comprising: a gasstripper column adapted to receive the liquid phased contaminatedprimary coolant, the gas stripper column having, a distributor memberconfigured along the column and adapted to evenly distribute the liquidphased contaminated primary coolant for flowing in the column, and aseparation member disposed in disposed the column below the distributormember, the separation member having a structured packing;
 8. Anelectrical re-boiler member configured along the column and adapted toheat the primary coolant to a gaseous phase, the gaseous phased coolantraises counter current to the liquid phased contaminated primary coolantin the column so as the separation member enables maximum contact of theliquid phased primary coolant with the gaseous phased primary coolantraising counter current to liquid phased contaminated primary coolant tobe dissolved to obtain vapour phased; and a condenser arrangementintegral to the gas stripper column to receive and condense the vapourphased primary coolant so as to enable non-condensable gases to bedischarged and return of the condensate to the column.